A Review of the Epidemiology of Human Immunodeficiency Virus (HIV) and Sexually Transmitted Infections (STI) - Globally and in Singapore

In recent years HIV infections have declined in many parts of the world, however, there are still 35 million persons living with HIV infection and 2.1 million new infections occurred in 2011 worldwide. In many areas HIV continues to affect certain at risk communities viz. men who have sex with men, sex workers, clients of sex workers and injecting drug users. In Singapore the number of newly diagnosed HIV infections appears to have stabilised, however the current trend is that infected individuals are presenting at a late stage of infection and more HIV infections are being diagnosed among MSM and fewer in heterosexuals. The trend for other sexually-transmitted infections is generally stable, with gonorrhea, Chlamydia trachomatis infection and anogenital herpes showing decreases, whilst the incidence of syphilis showed an increase in 2012. Interviews with patients attending the DSC Clinic indicate that most STIs are contracted locally from casual partners. Unregulated sex workers are more frequently cited as primary contacts than are local regulated sex workers, who continue to have very low levels of STIs, underlining the benefits of the programme of routine screening, treatment and condom negotiation skills training provided by the Department of STI Control (DSC) Clinic in Singapore.

Challenges of respondent driven sampling to assess sexual behaviour and estimate the prevalence of human immunodeficiency virus (HIV) and syphilis in men who have sex with men (MSM) in Singapore

There is a lack of representative samples to provide reliable and accurate seroprevalence of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) as well as behavioural information among men who have sex with men (MSM) in Singapore. We used respondent driven sampling (RDS) to recruit MSM. Participants completed a survey used by Asian Internet MSM Sex Survey (AIMSS) and were tested for HIV and syphilis. We compared the characteristics of the RDS participants with STI diagnosis against those who did not have any STI diagnosis in the past 6 months. We compared RDS participants with AIMSS participants. Of 72 MSM recruited, 1 was positive for HIV (1.3%) and 4 (5.5%) tested positive for syphilis. Median age was 30 years and majority was Chinese (69.4%). RDS participants who had any STI diagnosis reported to have more use of recreational drugs (P = 0.006), and lower condom use (P = 0.054). Comparing RDS participants (n = 72) with the AIMSS participants (n = 2075), RDS respondents had ≥1 male partner in the past 6 months (P = 0.003), more casual sex partners (P = 0.012) and more STI symptoms (P = 0.019). There was no difference in terms of HIV testing and recreational drug use. The HIV and syphilis seroprevalence rates from our study are similar to previous reports conducted in high-risk MSM. In contrast to other settings, RDS did not work well among MSM in Singapore. The public health implications of our study highlight the challenges in obtaining data for HIV surveillance in assessing prevalence and risk behaviours among MSM.

Biomedical strategies for human immunodeficiency virus (HIV) prevention? A new paradigm

<p><b>INTRODUCTION</b>This article presents recent developments in biomedical interventions for prevention of sexual transmission of the human immunodeficiency virus (HIV) infection.</p><p><b>MATERIALS AND METHODS</b>A review of results from randomised clinical trials on the use of antiretroviral (ARV) medications and other biomedical methods to prevent the transmission and acquisition of HIV infection.</p><p><b>RESULTS</b>Pre-exposure prophylaxis (PrEP) refers to the provision of ARV medications to uninfected persons at high risk of HIV infection either in the form of topical agents, e.g. vaginal microbicide gels, or orally administered tablets. The Caprissa study demonstrated the efficacy of vaginal microbicides, the Vaginal and Oral Interventions to Control the Epidemic (VOICE) study however was not able to confirm these results. Oral PrEP was found to be efficacious in the iPrEx study on men who have sex with men (MSM), and among heterosexual couples in the Partners-PrEP and the TDF2 studies in Africa. The HPTN 052 trial demonstrated that the provision of early ARV treatment was able to prevent transmission of HIV by 92% compared with delayed treatment. This has led to enthusiasm to roll out treatment as prevention (TasP) programmes. Encouraging results from studies on male circumcision to prevent HIV acquisition have resulted in several implementation projects in Africa. Another encouraging result has been the success, albeit modest, of the prime-boost combination RV144 vaccine trial in Thailand.</p><p><b>CONCLUSION</b>New advances in prevention strategies are urgently needed to slow down the HIV pandemic. Recent developments particularly in the form of PrEP and TasP have given new hope that we will be able to achieve this goal.</p>